Chronic Pain

Essentials

• The principal treatment responsibility of pain patients lies with the primary health care. Specialists are consulted with when necessary. A good treatment relationship with the own family doctor is fundamental in the treatment of chronic pain.
• The tasks in the primary health care include
  • clinical examination of pain patients (history and physical examination), complemented if necessary with further tests available in the primary care, with the aim of
    • identifying the type of pain (nociceptive, neuropathic, other)
    • diagnosing the underlying disease causing the pain
    • mapping of the psychosocial background factors that may contribute to the pain becoming chronic: the patient's own view of the pain and its significance, the patient's mood using DEPS screening, occupational and family situation, use of alcohol or drugs
  • causal or symptomatic treatment of pain according to the local agreements concerning the division of responsibilities between primary and specialised care.
• Patients in whom the pain cannot be sufficiently relieved in the primary care are referred to specialized care.
• Pain is documented on every visit by using a visual analogue scale (VAS) for pain (0-10), a numerical rating scale (NRS; 0-10) or a pain drawing.
• Rehabilitation is arranged for patients with poor treatment response to help with adapting to and coping with the symptoms.

General

• Pain in considered chronic when it has continued for more than 3 months or has lasted longer than what is the normal healing time of tissues.
• Neuropathic pain is caused by a damage in the pain pathway itself.
• Depression, suffering and anxiety are often associated with chronic pain. The patient's psychosocial condition is taken into account in treatment and rehabilitation.
• The pathophysiology of the pain is assessed as carefully as possible and treatment is planned according to the aetiology of pain.
• By treating acute pain as well as possible, pain can be prevented from becoming chronic.

Types of chronic pain

Examining a patient with pain

• Thorough history: the start and development of the symptoms, earlier examinations and treatments, present symptoms and functional ability, life situation, family, community factors at work etc.
• A visual analogue scale (VAS; scale 0-10, 0 = no pain at all, 10 = worst conceivable pain) or a numerical rating scale (NRS; 0-10) is used to measure pain. These can be complemented with a pain drawing.
• The pain is measured and documented on each visit.
• Sensory changes and location of the pain observed by the patient should be documented in a pain drawing.
• Pay attention to skin temperature, vitality and sweating (the activity of sympathetic nervous system).
• Neuropathic pain
  • Test the following senses in neurological examination: touch, sharp touch, heat, vibration, and cold, as well as the reaction to a normally painless stimulus, such as gentle stroking and light pressure of the skin.
  • Neurological examination Neurological Examination including tests for motor function, reflexes and cranial nerves give an idea of the location of the injury. A careful sensory examination helps in tailoring the treatment and later in assessing the treatment response.
  • Normal result in electroneuromyography (ENMG) Clinical Neurophysiology in Diagnostics does not exclude the possibility of peripheral neuropathy because ENMG does not provide information on the status of the small sensory fibers.

Treatment of chronic pain Antipsychotics for Acute and Chronic Pain, Injection Therapy for Subacute and Chronic Low-Back Pain, Effectiveness and Complications of Adhesiolysis in the Management of Chronic Spinal Pain, Exercises for Mechanical Neck Disorders

• Treatment is tailored individually depending on the mechanisms of pain and the patient's characteristics by testing one method at a time and by combining treatments based on different mechanisms.
• In many cases the treatment is merely symptomatic; aetiological treatment should be given immediately (e.g. relieving a compressed nerve).
• Symptomatic treatment is the more effective the earlier it is begun.
• Understanding the psychosocial situation of the pain patient

Opioids in chronic pain Opioid Switching to Improve Pain Relief and Drug Tolerability, Opioids for Neuropathic Pain, Opioids for Chronic Non-Cancer Pain, Oxycodone for Neuropathic Pain in Adults

• TramadolTramadol for Neuropathic Pain is to some extent effective in the treament of pain related to diabetic neuropathy, postherpetic neuralgia and neuropathic pain associated with spinal cord injury.
• Strong opioids are mainly used only when all other alternatives have been tried. The aim of opioid treatment is the alleviation of pain and the improvement of functional ability of the patient.
• If the diagnosis is clear and the need for an opioid is of short duration, e.g. in an osteoporotic vertebral fracture or in intense herpes zoster pain in an elderly patient, opioid therapy can be started sooner.
• The aetiology of the pain should be investigated.
• Other indications
  • The pain is clearly alleviated with an opioid and the patient's functional capacity improves.
  • The patient does not have a tendency for drug abuse.
  • The patient does not suffer from untreated anxiety or depression.
• Opioid therapy should preferably be started as the joint decision of two physicians. The implementation of the therapy should be the responsibility of only one doctor, with follow up at 1-3-month intervals. If the effect proves to be only modest and/or the adverse effects are troublesome, the opioid drug is slowly tapered off.
• The administration is started with an oral preparation and the dose is raised gradually over 4-8 weeks. The drug should be taken regularly, not "as needed". In the treatment of other types of pain than cancer pain, long-acting (slow release) opioid tablets are used.
• Concurrently with opioid therapy, a drug for constipation (e.g. lactulose) is started because constipation is commonly associated with opioid use and is often troublesome if not treated. A combination of oxycodone and naloxone is less constipatory than oxycodone alone. Opioid-induced constipation in patients for whom a laxative (or laxatives) have not provided adequate response can be treated with naloxegol (25 mg per day).
• The patient should be well informed of the principles of medication, and he/she may increase the dose only according the previously agreed scheme.
• Other methods of pain treatment are continued.
• Opioids are used only to treat pain. Specific medication is used to treat anxiety and depression.
• Opioid therapy for problem patients and those with chronic (but non malign) pain with strong opioids should be started in special pain management units.
• The risk of abuse may be diminished by an agreement made with the patient and the local pharmacy concerning supervised drug purchasing.

Tricyclic antidepressants

• Analgetic effect is independent of depression.
• Lower doses are needed for pain alleviation than for reducing depression.
• There is most research data on amitriptyline, which exerts an analgetic effect already in 4-5 days. Nortriptyline is as effective as amitriptyline but the adverse effects are milder.
• Tricyclic antidepressants are drugs of choice in neuropathic pain Antidepressants for Neuropathic Pain provided that there are no contraindications like arrhythmias, difficulty urinating, or orthostatic hypotension.
• Start with small evening doses, starting dose 10-25 mg. The drug also improves the quality of sleep.
• The dose is raised by 10 mg every other day, until maximal pain relief is achieved or side effects (tiredness, dry mouth, constipation, voiding problems, orthostatic hypotension) prevent raising the dose.
• The benefit can be assessed when the dose has been constant for 2 weeks.

Other antidepressants

• Drugs in the SNRI group (serotonin norepinephrine reuptake inhibitors) have similar effect profile to amitriptyline but the frequency of troublesome anticholinergic adverse effects is lower. There is strong evidence on venlafaxine Venlafaxine in the Treatment of Neuropathic Pain and duloxetine Duloxetine for Treating Painful Neuropathy, Chronic Pain or Fibromyalgia in the treatment of neuropathic pain. Besides tricyclic antidepressants and gabapentinoids, SNRIs are first line drugs in the treatment of peripheral neuropathic pain. Diabetic neuropathic pain is an official indication of duloxetine.
  • The dosage is the same as in the treatment of depression.
• The analgesic effect of selective serotonin reuptake inhibitors (SSRIs) is weak The Efficacy of Ssris in the Management of Chronic Pain and they are only used for the treatment of depression in pain patients.
  • Caution is warranted for concomitant use of SSRIs and tramadol because of the possibility of the serotonin syndrome Neuroleptic Malignant Syndrome (Nms).

Antiepileptic medications Carbamazepine for Acute and Chronic Pain, Nortriptyline and Gabapentin, Alone and in Combination for Neuropathic Pain, Pregabalin for Acute and Chronic Pain in Adults, Gabapentin for Chronic Neuropathic Pain in Adults

• Good evidence of effectiveness in pain caused by nerve injury
  • Carbamazepine or oxcarbazepine in trigeminal neuralgia. Carbamazepine is the first line drug for trigeminal neuralgia Trigeminal Neuralgia and other Facial Pain. Oxcarbazepine has less interactions.
  • Pregabalin and gabapentin in peripheral and central, lamotrigine in central neuropathic pain.
• For patients with contraindications for tricyclic drugs, pregabalin and gabapentin are the first line drugs in the treatment of neuropathic pain, except in trigeminal neuralgia.
• Pregabalin and gabapentin are effective in postherpetic neuralgia and in diabetic neuropathic pain.
  • Pregabalin is dosed at 75 mg × 2 for a week, then at 150 mg × 2 for another week and then 300 mg × 2 if the pain is not sufficiently alleviated with the lower doses. Pregabalin has been shown to be effective in relieving central neuropathic pain in patients with spinal cord injury.
  • Gabapentin is started at 300 mg in the evening and the dosage is increased by 300 mg every 1-3 days up to 3 600 mg/24h if needed. The daily gabapentin dosage should be divided into three parts to ensure an even effect.

Topical drugs Topical Capsaicin (Low Concentration) for Chronic Neuropathic Pain in Adults, Topical Rubefacients for Acute and Chronic Pain in Adults, Topical Nsaids for Chronic Musculoskeletal Pain in Adults

• Topical anaesthetic (e.g., EMLA^® ) may be used for post-herpetic pain if the patient feels a light touch of the skin as painful.

TENS therapy (transcutaneous electrical nerve stimulation) Transcutaneous Electrical Nerve Stimulation (Tens) Versus Placebo for Chronic Low Back Pain, Transcutaneous Electrical Nerve Stimulation (Tens) for Chronic Pain

• In musculosceletal pain (fibromyalgia, arthritis and arthrosis) the electrodes can be placed in the area of pain or close to it. Treatment targeted at trigger points reduces sensitivity to pressure and relaxes muscles.
• In post-herpetic neuralgia the electrodes are placed above or below the sick dermatome.
• In nerve injury pain the electrode is placed normally on the area of skin with a sense of touch. Areas without sense of touch do not contain sensory fibres and in the area of sensitized skin the stimulation would be intolerably strong. The electrodes can also be placed on the corresponding dermatome on the healthy side.
• The treatment is most effective in the beginning. In some patients the effect wears out in long-term therapy.
• Cardiac pacemaker is a contraindication.

Acupuncture

• Most useful in mild nociceptive tension-type pains affecting the musculoskeletal system and in migraine. See Acupuncture.
• Acupuncture may trigger autonomic reactions such as nausea, bradycardia and tiredness.

Spinal cord stimulation , Spinal Manipulative Therapy for Chronic Low-Back Pain

• Administered through electrodes by means of a pulse generator. The electrodes are implanted into the epidural space so that the stimulation is directed at the site in the spinal cord corresponding to the pain area.
• Relieves pain and improves the quality of life in patients with peripheral neuropathic pain or CRPS Complex Regional Pain Syndrome (Crps).
• Careful patient selection, avoidance of delays, service provision in units with extensive experience and high competence, as well as incorporating spinal cord stimulation into a comprehensive multidisciplinary therapeutic approach are prerequisites for maximum utilization of this treatment mode.

Local anaesthetic injections

• Series of injections of local anaesthetics have earlier been used in the management of chronic pain, but there is no evidence on their effect.
• The analgetic effect is longer than the pharmacological anaesthetic effect. Epidural and spinal anaesthesias are given only by hospital pain clinics.
• The injections are helpful because the analgesia normalizes the function and motor activity on the painful area (eg. resolves muscle spasms).

Management of chronic pain in cooperation between primary and specialist care , Psychological Therapies for the Management of Chronic Pain in Adults, Psychosocial Interventions for Chronic Orofacial Pain

• The principal treatment responsibility of pain patients lies with the primary health care. Specialists are consulted with when necessary. The primary health care is responsible for comprehensive follow-up care.
• In specialised care, the management of pain in patients with multiple diseases and multiple problems should be carried out in cooperation between different specialties so that one unit has the coordination responsibility and the other specialties provide consultation help.
• Major hospitals have pain clinics where specialists representing at least two different fields are in charge of the treatment. The clinics usually have a multidisciplinary team with an anaesthesiologist specialized in pain management, physiatrist, psychologist, psychiatrist, neurologist, orthopaedist and social worker.
• The role of the psychologist is prominent when a patient tries to identify his/her own mechanisms of pain management.
• There is a strong body of evidence on the effectiveness of multidisciplinary psychological treatment provided in pain clinics and based on a cognitive-behavioural approach in the treatment of severe chronic pain.